JPS6479626A - Automatic sonic velocity measuring apparatus - Google Patents

Abstract

PURPOSE:To automatically measure the sonic velocity of a specimen, by controlling the pulse width of a burst like ultrasonic wave and measuring a peak in required timing. CONSTITUTION:A transmitting circuit controller 10 respectively sends a frequency converting signal and a signal of a short pulse width to a synthesizer 2 and a gate amplifier 3 and an oscillation circuit 1 excites an ultrasonic vibrator 5 on the basis of said signals to transmit a burst like ultrasonic wave. The ultrasonic wave is reflected from the bottom surface of a specimen 4 through a buffer rod 6 to be received by the vibrator 5. The peak detector 9 connected to an envelope detector 8 detects the amplitude change state of the reflected wave and a peak detection time setting device 13 measures the relation between a peak detection time and a peak. Herein, the setting device 13 sets a pulse width and timing at the initial stage of measurement so as to obtain a short pulse width and subsequently makes the pulse width long to obtain such a state that the multiple reflected waves from the specimen generate interference and, when the peak of a synthetic wave is measured by the detector 9, the sonic velocity of the specimen can be calculated from the interval of the max. or min. value of the peak to certain frequency.